The access switches show no errors. THe core switches are 3850XS-12. THe access switches are HP 3810. The SFPs are LH on both side (SFPS are vendor specific, Cisco SFP on Cisco and HP on HP). Fiber is multimode 62.5, and the distances is roughly 1000-1500.

Are input errors and CRC always supposed to be 0? Is 30 too high on interface 3 on core 2? It was recommended that mode conditioners are used, but I don't have any. Any suggestions or input would be great!

In my opinion is not worrying. I would keep an eye to check further figures to compare.

If it is possible you can interchange the channels to see if always is the same channel. In such a case I would try to contact the manufacturer to test the hardware. Anyway, I'd give it a margin with that CRC error rate.

A lot of things can cause input errors, including simple things like plugging a cable into an interface that isn't shut down. That is a really low number. You can clear the interface counters and/or monitor for a while, but I wouldn't worry about it unless you see them incrementing.

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